Diet Rich in Olive Oil, Nuts Beat Low-Fat Diet in 3-Month Study of High-Risk Adults
July 5, 2006 -- Traditional Mediterranean diets that include nuts and olive oil may help protect the heart in those at high risk for .
That news comes from Spain's Ramon Estruch, MD, PhD, and colleagues. Estruch works in the internal medicine department at the University of Barcelona Hospital Clinic.
Estruch's team studied 772 adults at high risk for heart disease. Participants met at least one of two criteria:
- Type 2
- 3 or more heart disease risk factors: smoking, , high levels of LDL ("bad") cholesterol, low levels of HDL ("good") cholesterol, family history of heart disease, and overweight BMI (body mass index).
Participants were 55 to 80 years old (average age: 68) and 90% were overweight or obese, based on BMI standards. None were known to have heart disease, severe chronic illness, or addiction to drugs or alcohol.
The researchers randomly assigned participants to spend three months on one of the following diets:
- Low-fat diet limiting all types of fats
- Mediterranean diet with free supplies of walnuts, almonds, and hazelnuts
- Mediterranean diet with free supplies of virgin olive oil
A dietitian taught each of the Mediterranean diet groups about their assigned diet and provided shopping lists and recipes. The researchers also supplied olive oil to one Mediterranean diet group and walnuts, hazelnuts, and almonds to the other Mediterranean diet group.
That was a pretty big head start, compared with the low-fat diet group. Those participants only got a low-fat diet brochure based on American Heart Association guidelines from 2000. They didn't get any classes, shopping lists, or recipes.
It's often tough to get people to comply with diet studies, the researchers note. Here's what happened in their study:
- Those in the low-fat group trimmed only a little fat from their diets.
- All 3 groups started eating more vegetables, legumes, fruit, and fish. They also cut back on meat, sweets, and dairy products.
- All 3 groups cut back on saturated fat (olive oil contains unsaturated fat).
- The 2 Mediterranean diet groups cut their cholesterol consumption.
- The nut eaters added more fiber and ate fewer carbohydrates.
- Weight held steady in all 3 groups.